A 2 kg ball rolls from rest from point **A **on a frictionless track **ABCD**, as shown below. The horizontal section, **BC**, of the track is 5 cm above the ground. The ball reaches point **D**, 30 cm above the ground, at a speed of 1,71 m∙s^{-1}.

5.1 Write down ONE term for the following statement:

*The sum of gravitational potential energy and kinetic energy * (1)

5.2 Calculate the:

5.2.1 Mechanical energy of the ball at point **D **(4)

5.2.2 Initial height **h** of the ball at point **A **(3)

5.2.3 Speed of the ball while it moves between point **B **and point **C **(3)

5.3 The 2 kg ball is now replaced with a 4 kg ball.

How will the speed of the 4 kg ball compare to the speed of the 2 kg ball at point **D**? Choose from GREATER THAN, SMALLER THAN or EQUAL TO. Give a reason for the answer. (2)

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